Revert "Kernel: Don't clone kernel mappings for bottom 2 MiB VM into processes"

This reverts commit da7b21dc06.

This broke SMP boot, oops! :^)

Kernel/VM/PageDirectory.cpp

@@ -135,6 +135,13 @@ PageDirectory::PageDirectory(Process& process, const RangeAllocator* parent_rang
         MM.unquickmap_page();
     }
 
+    // Clone bottom 2 MiB of mappings from kernel_page_directory
+    PageDirectoryEntry buffer;
+    auto* kernel_pd = MM.quickmap_pd(MM.kernel_page_directory(), 0);
+    memcpy(&buffer, kernel_pd, sizeof(PageDirectoryEntry));
+    auto* new_pd = MM.quickmap_pd(*this, 0);
+    memcpy(new_pd, &buffer, sizeof(PageDirectoryEntry));
+
     // If we got here, we successfully created it. Set m_process now
     m_process = &process;